Input device transmitter path error diagnosis

ABSTRACT

A processing system configured for capacitive sensing comprises transmitter circuitry, a first internal diagnostic mechanism, and a determination module. The transmitter circuitry is coupled with a first transmitter path of a plurality of transmitter paths and configured to transmit a first transmitter signal with the first transmitter path, wherein each transmitter path of the plurality of transmitter paths is configured for capacitive sensing. The first internal diagnostic mechanism is coupled to a second transmitter path of the plurality of transmitter paths. The first internal diagnostic mechanism is configured to acquire a first resulting signal while the transmitter circuitry transmits the first transmitter signal with the first transmitter path, wherein the first internal diagnostic mechanism comprises a selectable leakage path coupled to the transmitter circuitry. The determination module is further configured to determine that the first transmitter path is ohmically coupled to the second transmitter path of the plurality of transmitter paths based upon the first resulting signal.

CROSS-REFERENCE TO RELATED APPLICATIONS—CONTINUATION

This application is a continuation application of and claims the benefitof U.S. patent application Ser. No. 13/012,943 filed on Jan. 25, 2011now U.S. Pat. No. 8,692,794 entitled “INPUT DEVICE TRANSMITTER PATHERROR DIAGNOSIS” by Wen Fang and assigned to the assignee of the presentapplication.

BACKGROUND

Input devices including proximity sensor devices (also commonly calledtouchpads or touch sensor devices) are widely used in a variety ofelectronic systems. A proximity sensor device typically includes asensing region, often demarked by a surface, in which the proximitysensor device determines the presence, location and/or motion of one ormore input objects. Proximity sensor devices may be used to provideinterfaces for the electronic system. For example, proximity sensordevices are often used as input devices for larger computing systems(such as opaque touchpads integrated in, or peripheral to, notebook ordesktop computers). Proximity sensor devices are also often used insmaller computing systems (such as touch screens integrated in cellularphones).

SUMMARY

A processing system configured for capacitive sensing comprisestransmitter circuitry, a first internal diagnostic mechanism, and adetermination module. The transmitter circuitry is configured totransmit during a first time period with a first transmitter path of aplurality of transmitter paths in an input device. Each transmitter pathof the plurality of transmitter paths is configured for capacitivesensing. The first internal diagnostic mechanism comprises a selectableleakage path. The selectable leakage path is configured to be coupledwith the transmitter circuitry. The determination module is configuredto determine if a discontinuity exists within the first transmitter pathbased on a discharge rate for the first transmitter path. The dischargerate is acquired during a second time period via the selectable leakagepath of the first internal diagnostic mechanism, wherein the second timeperiod occurs after the first time period.

BRIEF DESCRIPTION OF DRAWINGS

The drawings referred to in this Brief Description of Drawings shouldnot be understood as being drawn to scale unless specifically noted. Theaccompanying drawings, which are incorporated in and form a part of theDescription of Embodiments, illustrate various embodiments of thepresent invention and, together with the Description of Embodiments,serve to explain principles discussed below, where like designationsdenote like elements, and:

FIG. 1A is a block diagram of an example input device, in accordancewith embodiments;

FIG. 1B shows a portion of an example sensor electrode pattern which maybe utilized to generate all or part of the sensing region of an inputdevice, according to an embodiment;

FIG. 1C shows an example of a transmitter path, according to variousembodiments;

FIGS. 2A and 2B illustrate major components of transmitter paths in twoexample input devices, in accordance with embodiments;

FIG. 3 illustrates an example processing system which may be utilizedwith an input device, according to various embodiments;

FIG. 4 illustrates an internal diagnostic mechanism coupled with atransmitter circuit, in accordance with an embodiment; and

FIGS. 5A, 5B, and 5C illustrate a flow diagram of an example method ofinput device transmitter path error diagnosis, in accordance withembodiments.

DESCRIPTION OF EMBODIMENTS

The following Description of Embodiments is merely provided by way ofexample and not of limitation. Furthermore, there is no intention to bebound by any expressed or implied theory presented in the precedingbackground or brief summary, or in the following detailed description.

Overview of Discussion

Herein, various embodiments are described that provide input devices andmethods that facilitate improved usability. In various embodimentsdescribed herein, the input device may be a capacitive sensing device.

Discussion begins with a description of an example input device withwhich or upon which various embodiments described herein may beimplemented. An example processing system and components thereof arethen described. The processing system may be utilized with an inputdevice such as the capacitive sensing device, or with some otherdevice/system. Operation of the processing system and its components arefurther described in conjunction with description of an example methodof input device transmission error diagnosis.

Example Input Device

FIG. 1A is a block diagram of an example input device 100, in accordancewith embodiments of the invention. The input device 100 may beconfigured to provide input to an electronic device 150. The inputdevice 100 may be configured to provide input to an electronic system(not shown). As used in this document, the term “electronic system” (or“electronic device”) broadly refers to any system capable ofelectronically processing information. Some non-limiting examples ofelectronic systems include personal computers of all sizes and shapes,such as desktop computers, laptop computers, netbook computers, tablets,web browsers, e-book readers, and personal digital assistants (PDAs).Additional example electronic systems include composite input devices,such as physical keyboards that include input device 100 and separatejoysticks or key switches. Further example electronic systems includeperipherals such as data input devices (including remote controls andmice), and data output devices (including display screens and printers).Other examples include remote terminals, kiosks, and video game machines(e.g., video game consoles, portable gaming devices, and the like).Other examples include communication devices (including cellular phones,such as smart phones), and media devices (including recorders, editors,and players such as televisions, set-top boxes, music players, digitalphoto frames, and digital cameras). Additionally, the electronic systemcould be a host or a slave to the input device.

The input device 100 can be implemented as a physical part of theelectronic system, or can be physically separate from the electronicsystem. As appropriate, the input device 100 may communicate with partsof the electronic system using any one or more of the following: buses,networks, and other wired or wireless interconnections. Examplesinclude, but are not limited to: Inter-Integrated Circuit (I²C), SerialPeripheral Interface (SPI), Personal System 2 (PS/2), Universal SerialBus (USB), Bluetooth®, Radio Frequency (RF), and Infrared DataAssociation (IrDA).

In FIG. 1A, input device 100 is shown as a proximity sensor device (alsooften referred to as a “touchpad” or a “touch sensor device”) configuredto sense input provided by one or more input objects 140 in a sensingregion 120. Some example input objects include fingers and styli, asshown in FIG. 1A.

Sensing region 120 encompasses any space above, around, in and/or nearthe input device 100 in which the input device 100 is able to detectuser input (e.g., user input provided by one or more input objects 140).The sizes, shapes, and locations of particular sensing regions may varywidely from embodiment to embodiment. In some embodiments, the sensingregion 120 extends from a surface of the input device 100 in one or moredirections into space until signal-to-noise ratios prevent sufficientlyaccurate object detection. The distance to which this sensing region 120extends in a particular direction, in various embodiments, may be on theorder of less than a millimeter, millimeters, centimeters, or more, andmay vary significantly with the type of sensing technology used and theaccuracy desired. Thus, some embodiments sense input that comprises nocontact with any surfaces of the input device 100, contact with an inputsurface (e.g. a touch surface) of the input device 100, contact with aninput surface of the input device 100 coupled with some amount ofapplied force or pressure, and/or a combination thereof. In variousembodiments, input surfaces may be provided by surfaces of casingswithin which the sensor electrodes reside, by face sheets applied overthe sensor electrodes or any casings, etc. In some embodiments, thesensing region 120 has a rectangular shape when projected onto an inputsurface of the input device 100.

The input device 100 may utilize any combination of sensor componentsand sensing technologies to detect user input in the sensing region 120.The input device 100 comprises one or more sensing elements fordetecting user input. As several non-limiting examples, the input device100 may use capacitive, elastive, resistive, inductive, magneticacoustic, ultrasonic, and/or optical techniques.

Some implementations are configured to provide images that span one,two, three, or higher dimensional spaces. Some implementations areconfigured to provide projections of input along particular axes orplanes.

In some capacitive implementations of the input device 100, voltage orcurrent is applied to create an electric field. Nearby input objectscause changes in the electric field, and produce detectable changes incapacitive coupling that may be detected as changes in voltage, current,or the like.

Some capacitive implementations utilize arrays or other regular orirregular patterns of capacitive sensing elements to create electricfields. In some capacitive implementations, separate sensing elementsmay be ohmically shorted together to form larger sensor electrodes. Somecapacitive implementations utilize resistive sheets, which may beuniformly resistive.

Some capacitive implementations utilize “self capacitance” (or “absolutecapacitance”) sensing methods based on changes in the capacitivecoupling between sensor electrodes and an input object. In variousembodiments, an input object near the sensor electrodes alters theelectric field near the sensor electrodes, thus changing the measuredcapacitive coupling. In one implementation, an absolute capacitancesensing method operates by modulating sensor electrodes with respect toa reference voltage (e.g. system ground), and by detecting thecapacitive coupling between the sensor electrodes and input objects.

Some capacitive implementations utilize “mutual capacitance” (or“transcapacitance”) sensing methods based on changes in the capacitivecoupling between sensor electrodes. In various embodiments, an inputobject near the sensor electrodes alters the electric field between thesensor electrodes, thus changing the measured capacitive coupling. Inone implementation, a transcapacitive sensing method operates bydetecting the capacitive coupling between one or more transmitter sensorelectrodes (also “transmitter electrodes” or “transmitters”) and one ormore receiver sensor electrodes (also “receiver electrodes” or“receivers”). Transmitter sensor electrodes may be modulated relative toa reference voltage (e.g., system ground) to transmit transmittersignals. Receiver sensor electrodes may be held substantially constantrelative to the reference voltage to facilitate receipt of resultingsignals comprising response(s) corresponding to the transmittersignal(s). Sensor electrodes may be dedicated transmitters or receivers,or may be configured to both transmit and receive.

In FIG. 1A, a processing system 110 is shown as part of the input device100. The processing system 110 is configured to operate the hardware ofthe input device 100 to detect input in the sensing region 120. Theprocessing system 110 comprises parts of or all of one or moreintegrated circuits (ICs) and/or other circuitry components. (Forexample, a processing system for a mutual capacitance sensor device maycomprise transmitter circuitry configured to transmit signals withtransmitter sensor electrodes, and/or receiver circuitry configured toreceive signals with receiver sensor electrodes). In some embodiments,the processing system 110 also comprises electronically-readableinstructions, such as firmware code, software code, and/or the like. Insome embodiments, components composing the processing system 110 arelocated together, such as near sensing element(s) of the input device100. In other embodiments, components of processing system 110 arephysically separate with one or more components close to sensingelement(s) of input device 100, and one or more components elsewhere.For example, the input device 100 may be a peripheral coupled to adesktop computer, and the processing system 110 may comprise softwareconfigured to run on a central processing unit of the desktop computerand one or more ICs (perhaps with associated firmware) separate from thecentral processing unit. As another example, the input device 100 may bephysically integrated in a phone, and the processing system 110 maycomprise circuits and firmware that are part of a main processor of thephone. In some embodiments, the processing system 110 is dedicated toimplementing the input device 100. In other embodiments, the processingsystem 110 also performs other functions, such as operating displayscreens, driving haptic actuators, etc.

The processing system 110 may be implemented as a set of modules thathandle different functions of the processing system 110. Each module maycomprise circuitry that is a part of the processing system 110,firmware, software, or a combination thereof. In various embodiments,different combinations of modules may be used. Example modules includehardware operation modules for operating hardware such as sensorelectrodes and display screens, data processing modules for processingdata such as sensor signals and positional information, and reportingmodules for reporting information. Further example modules includesensor operation modules configured to operate sensing element(s) todetect input, identification modules configured to identify gesturessuch as mode changing gestures, and mode changing modules for changingoperation modes.

In some embodiments, the processing system 110 responds to user input(or lack of user input) in the sensing region 120 directly by causingone or more actions. Example actions include changing operation modes,as well as GUI actions such as cursor movement, selection, menunavigation, and other functions. In some embodiments, the processingsystem 110 provides information about the input (or lack of input) tosome part of the electronic system (e.g. to a central processing systemof the electronic system that is separate from the processing system110, if such a separate central processing system exists). In someembodiments, some part of the electronic system processes informationreceived from the processing system 110 to act on user input, such as tofacilitate a full range of actions, including mode changing actions andGUI actions.

For example, in some embodiments, the processing system 110 operates thesensing element(s) of the input device 100 to produce electrical signalsindicative of input (or lack of input) in the sensing region 120. Theprocessing system 110 may perform any appropriate amount of processingon the electrical signals in producing the information provided to theelectronic system. For example, the processing system 110 may digitizeanalog electrical signals obtained from the sensor electrodes. Asanother example, the processing system 110 may perform filtering orother signal conditioning. As yet another example, the processing system110 may subtract or otherwise account for a baseline, such that theinformation reflects a difference between the electrical signals and thebaseline. As yet further examples, the processing system 110 maydetermine positional information, recognize inputs as commands,recognize handwriting, and the like.

“Positional information” as used herein broadly encompasses absoluteposition, relative position, velocity, acceleration, and other types ofspatial information. Exemplary “zero-dimensional” positional informationincludes near/far or contact/no contact information. Exemplary“one-dimensional” positional information includes positions along anaxis. Exemplary “two-dimensional” positional information includesmotions in a plane. Exemplary “three-dimensional” positional informationincludes instantaneous or average velocities in space. Further examplesinclude other representations of spatial information. Historical dataregarding one or more types of positional information may also bedetermined and/or stored, including, for example, historical data thattracks position, motion, or instantaneous velocity over time.

In some embodiments, the input device 100 is implemented with additionalinput components that are operated by the processing system 110 or bysome other processing system. These additional input components mayprovide redundant functionality for input in the sensing region 120, orsome other functionality. FIG. 1A shows buttons 130 near the sensingregion 120 that can be used to facilitate selection of items using theinput device 100. Other types of additional input components includesliders, balls, wheels, switches, and the like. Conversely, in someembodiments, the input device 100 may be implemented with no other inputcomponents.

In some embodiments, the input device 100 comprises a touch screeninterface, and the sensing region 120 overlaps at least part of anactive area of a display screen. For example, the input device 100 maycomprise substantially transparent sensor electrodes overlaying thedisplay screen and provide a touch screen interface for the associatedelectronic system. The display screen may be any type of dynamic displaycapable of displaying a visual interface to a user, and may include anytype of light emitting diode (LED), organic LED (OLED), cathode ray tube(CRT), liquid crystal display (LCD), plasma, electroluminescence (EL),or other display technology. The input device 100 and the display screenmay share physical elements. For example, some embodiments may utilizesome of the same electrical components for displaying and sensing. Asanother example, the display screen may be operated in part or in totalby the processing system 110.

It should be understood that while many embodiments of the presentinvention are described in the context of a fully functioning apparatus,the mechanisms of the present invention are capable of being distributedas a program product (e.g., software) in a variety of forms. Forexample, the mechanisms of the present invention may be implemented anddistributed as a software program on information bearing media that arereadable by electronic processors (e.g., non-transitorycomputer-readable and/or recordable/writable information bearing mediareadable by the processing system 110). Additionally, the embodiments ofthe present invention apply equally regardless of the particular type ofmedium used to carry out the distribution. Examples of non-transitory,electronically readable media include various discs, memory sticks,memory cards, memory modules, and the like. Electronically readablemedia may be based on flash, optical, magnetic, holographic, or anyother storage technology.

FIG. 1B shows a portion of an example sensor electrode pattern which maybe disposed to generate all or part of the sensing region of an inputdevice, according to an embodiment. For purposes of clarity ofillustration and description, a simple rectangular pattern isillustrated, though it is appreciated that other patterns may beemployed. The sensing pattern is made up of a plurality of receiverelectrodes 170 (170-1, 170-2, 170-3, . . . 170-n) and a plurality oftransmitter electrodes 160 (160-1, 160-2, 160-3, . . . 160-n) whichoverlay one another and are disposed on a substrate 180. In thisexample, touch sensing pixels are centered at locations wheretransmitter and receiver electrodes cross. It is appreciated that someform of insulating material is typically disposed between transmitterelectrodes 160 and receiver electrodes 170. In one embodiment,transmitter electrodes 160 (160-1, 160-2, 160-3, . . . 160-n) andreceiver electrodes 170 (170-1, 170-2, 170-3, . . . 170-n) may bedisposed on a similar layer, where the transmitter electrode comprise aplurality of jumpers disposed on a second layer. In various embodiments,touch sensing includes sensing input objects anywhere in sensing region120 and may comprise: no contact with any surfaces of the input device100, contact with an input surface (e.g., a touch surface) of the inputdevice 100, contact with an input surface of the input device 100coupled with some amount of applied force or pressure, and/or acombination thereof.

FIG. 1C shows an example of a transmitter path 190, according to variousembodiments. FIG. 1C shows processing system 110 coupled with trace 195via connection 191-1 and trace 195 coupled with transmitter electrode160-1 via connection 191-2. Herein, at its longest, a transmitterelectrode along with a totality of the electrical pathway which couplesthe transmitter electrode to transmitter circuitry in a processor isconsidered to be a transmitter path. However, in some embodiments, suchas when a transmitter path error exists or when an input device is onlypartially assembled, a transmitter path may be shortened and/or includefewer components. Thus, as illustrated by FIG. 1C, transmitter path 190may comprise a transmitter electrode (e.g., 160-1), connections 191-1and 191-2 and trace 195. In one embodiment, a transmitter path includesconnection 191-1 and trace 195. In another embodiment, a transmitterpath includes connection 191-1, trace 195 and connection 191-2. In yet afurther embodiment, a transmitter path includes connection 191-1, trace195, connection 191-2 and transmitter electrode 160-1. In otherembodiments, the transmitter path may include other traces andconnections. For example, in one embodiment, connection 191-2 may coupletrace 195 with another trace, where that trace is then coupled withtransmitter electrode 160-1 through another connection. In suchembodiment, transmitter path 190 may include one or more of any trace,connection and transmitter electrode. Connection 191-1 and connection191-2 include hot bar connections, zero insertion force connections,bonding pads, and sensor channels. In other embodiment, connections191-1 and 191-2 include any device able to couple traces 150 withprocessing system 110 or transmitter electrode 160-1.

In other embodiments, plurality of transmitter electrodes 160 andplurality of receiver electrodes 170 are coupled to processing system110 though a plurality of traces, where each transmitter electrode andreceiver electrode is coupled to processing system 110 through adifferent trace. Further, in some embodiments, plurality of transmitterelectrodes 160 is coupled with a first plurality of traces, where theplurality of transmitter electrodes 160 and the first plurality oftraces are disposed on substrate 180. A connection device, comprising asecond plurality of traces, couples processing system 110 with atransmitter electrode of plurality of transmitter electrodes 160 bycoupling a trace of the first plurality of traces with a correspondingtrace of the second plurality of traces. Each of the second plurality oftraces is then coupled with a different connection of processing system110. In such an example, a transmitter path may include at least one ofa transmitter electrode, a corresponding trace of the first plurality oftraces, a corresponding trace of the second plurality of traces, anyconnection between corresponding traces, any connection between thetransmitter electrode and corresponding traces, and the connectionbetween the corresponding trace of the second plurality of traces andthe transmitter circuitry of processing system 110.

FIGS. 2A and 2B illustrate major components of transmitter paths in twoexample input devices, in accordance with embodiments. Input device 100Ais illustrated in FIG. 2A, while input device 100B is illustrated inFIG. 2B. Both of these input devices 100A and 100B are illustrated asbeing overlaid upon a display, however, embodiments described herein maybe utilized with input devices that are not implemented in conjunctionwith a display. In various embodiments, input devices 100A and 100B mayshare elements with the display. For example, transmitter electrodes 160may be shared between an input device (100A or 100B) and the display,where the transmitter electrodes 160 are configured for both capacitivesensing and display updating. In one embodiment, a common voltageelectrode (Vcom electrode) of the display is segmented to formtransmitter electrodes 160. In other embodiments, elements of inputdevices 100A and 100B may be disposed within the display such as beingdisposed on a polarizer, color filter panel or other substrate of thedisplay. In one embodiment, transmitter electrodes 160 and receiveelectrodes 170 may be disposed on a same layer of a substrate or ondifferent layers of a substrate: the substrate overlaid upon a display.

Input device 100A includes a clear transcapacitive touch screen 210 thatis configured with a sensor electrode pattern of transmitter electrodes160 and receiver electrodes 170 (see e.g., FIG. 1B for one example ofsuch a sensor electrode pattern). In many embodiments, the sensorelectrodes are made of transparent materials and/or are only accessibleon one end. As illustrated, touch screen 210 is disposed upon a glassshelf of a thin film transistor (TFT) glass 220 of a display. Processingsystem 110 is disposed upon flexible printed circuit (FPC) board 230A.FPC 230A includes a connector 235 for connecting to other electronicdevices (e.g., electronic device 150), a connector 237 for coupling withcomponents a display, and first portion (e.g., a socket) of a zeroinsertion force (ZIF) connection 241 for removably coupling with FPC240A. FPC 240A includes a second portion (e.g., pins that are configuredto fit into the ZIF socket) of ZIF connection 241, and a connector 245that couples with transmitter electrodes 160 and receiver electrodes 170of touch screen 210. Between the second portion of ZIF 241 and connector245, FPC 240A includes traces that couple transmitter circuitry ofprocessing system 110 with transmitter electrodes 160 and traces thatcouple receiver circuitry of processing system 110 with receiverelectrodes 170. In FIG. 2A, components that make up a transmitter pathinclude may include any one or more of: a transmitter circuit ofprocessing system 110A, ZIF connection 241, a trace on flexible printedcircuit 240A, connector 245, and a transmitter electrode (e.g., 160-1)on touch screen 210. It is appreciated that a short or open can occur atany location in this transmitter path, and that embodiments describedherein may be utilized to diagnose the presence of a short or open andin some instances, the component with in the transmitter path where theshort or open is located.

Input device 100B includes a clear transcapacitive touch screen 210 thatis configured with a sensor electrode pattern of transmitter electrodes160 and receiver electrodes 170 (see e.g., FIG. 1B for one example ofsuch a sensor electrode pattern). In many embodiments, the sensorelectrodes are made of transparent materials and/or are only accessibleon one end. As illustrated, touch screen 210 is disposed upon a glassshelf of a thin film transistor (TFT) glass 220 of a display. Processingsystem 110 is disposed upon flexible printed circuit (FPC) board 230B.FPC 230B includes a connector 235 for connecting to other electronicdevices (e.g., electronic device 150), a connector 237 for coupling withcomponents a display, and pads (not visible) to which a soldered hot barconnection is made for coupling with FPC 240B. FPC 240B includes hot barconnector 243, and a connector 245 that couples with transmitterelectrodes 160 and receiver electrodes 170 of touch screen 210. Betweenhot bar connector 243 and connector 245, FPC 240B includes traces thatcouple transmitter circuitry of processing system 110 with transmitterelectrodes 160 and traces that couple receiver circuitry of processingsystem 110 with receiver electrodes 170. In FIG. 2B, components thatmake up a transmitter path may include any one or more of: a transmittercircuit of processing system 110A, hot bar connector 243, a trace onflexible printed circuit 240B, connector 245, and a transmitterelectrode (e.g., 160-1) on touch screen 210. It is appreciated that ashort or open can occur at any location in this transmitter path, andthat embodiments described herein may be utilized to diagnose thepresence of a short or open and in some instances, the component withinthe transmitter path where the short or open is located.

Example Processing System

FIG. 3 illustrates an example processing system 110A which may beutilized with an input device (e.g., input device 100), according tovarious embodiments. Processing system 110A may be implemented with oneor more ASICs, one or more ICs, one or more controllers, or somecombination thereof. In one embodiment, processing system 110A iscommunicatively coupled with a plurality of transmitter and a pluralityof receiver electrodes that implement a sensing region 120 of an inputdevice 100. In one embodiment, of input device 100, processing system110A includes transmitter circuitry 305, receiver circuitry 315,demodulation circuitry 325, computation circuitry 335, internaldiagnostic mechanisms 345, and determination module 355. In someembodiments, processing system 110A and the input device 100, of whichit is a part, may be disposed in or communicatively coupled with anelectronic device 150, such as a display device, computer, or otherelectronic device.

Transmitter circuitry 305 operates to transmit transmitter signals onone or more transmitter electrodes 160. The signals that are transmittedon the transmitter electrodes each travel to a respective transmitterelectrode by way of a transmitter path. In one embodiment thetransmitter electrode is part of the transmitter path. Variousembodiments of transmitter paths have been previously described inconjunction with FIGS. 1C, 2A and 2B. In a given time interval,transmitter circuitry 305 may transmit a transmitter signal (waveform)on one or more of a plurality of transmitter electrodes 160. Transmittercircuitry 305 may also be utilized to couple one or more transmitterelectrodes 160 (and respective transmitter path(s)) of a plurality oftransmitter electrodes 160 to high impedance, ground, or to a constantvoltage when not transmitting a waveform on such transmitter electrodes.The transmitter signal may be a square wave, trapezoidal wave, or someother waveform.

Receiver circuitry 315 operates to receive resulting signals, viareceiver electrodes. The received resulting signals correspond to andinclude some version of the transmitter signal(s) transmitted via thetransmitter electrodes. These transmitted transmitter signals however,may be altered or changed in the resulting signal due to straycapacitance, noise, interference, and/or circuit imperfections amongother factors, and thus may differ slightly or greatly from theirtransmitted versions. Resulting signals may be received on one or aplurality of receiver electrodes during a time interval.

Demodulation circuitry 325 operates to demodulate the received resultingsignals that are acquired from one or more receiver electrodes 170. Inone embodiment, the resulting signals are or may be affected by userinput. For example, the received resulting signal may be affected inamplitude, phase or frequency by a user input such as placing an inputobject 140 within sensing region 120.

Computation circuitry 335 operates to compute/determine a measurement ofa change in transcapacitive coupling between a transmitter electrode anda receiver electrode. Computation circuitry 335 then uses thismeasurement of change in transcapacitive coupling to determine thepositional information of an input object (if any) with respect tosensing region 120. In one embodiment, the measurement of change isdetermined based on the demodulated output that is acquired bydemodulation circuitry 325.

Internal diagnostic mechanisms 345 include one or more internaldiagnostic mechanisms (e.g., 345-1 of FIG. 4). For example, in oneembodiment, each transmitter circuit (e.g. 305-1 of FIG. 4) oftransmitter circuitry 305 may be configured with its own diagnosticmechanism in the manner illustrated in FIG. 4. Internal diagnosticmechanisms 345 are employed by processing system 110A to monitortransmitter paths and to establish selectable weak leakage paths thatare coupled to transmitter paths. For example, a selectable leakage pathcan be selected in order to discharge a charge that has been driven ontoa transmitter path. An output of an internal diagnostic mechanism whichis coupled with a particular transmitter path can be monitored tomeasure any charge or signal on the transmitter path with which it iscoupled. Functioning of internal diagnostic mechanisms 345 will bedescribed in greater detail in conjunction with discussion of FIG. 4. Inone embodiment, internal diagnostic mechanisms 345 are disposed on thesame piece of silicon as part of the same integrated circuit astransmitter circuitry 305, thus eliminating the need for externaltesting appliances.

Determination module 355 receives output(s) from one or more internaldiagnostic mechanisms 345 and utilizes the outputs to determine whethera discontinuity (open) or an ohmic coupling (i.e., a short of somelevel) exists in one or more of the transmitter paths of an input deviceand, in some instances, to determine where in a particular transmitterpath (e.g., which component in the transmitter path) that an openexists. Determining the presence of an open or a short prevents adefective input device from exiting a production cycle, as it can beeither disposed of or repaired. Furthermore, determining the componentwithin the transmitter path that in which an open exists can facilitatea decision on repair or disposal. For instance, if the open isdetermined to be within the transmitter electrodes of a touch screen ortouch pad, the touch screen/touch pad will often be disposed of becauseit is too difficult to fix, however the other components in thetransmitter path may be saved and reused. Similarly, if the open isdetermined to be elsewhere within the input device (not in the touchscreen/touch pad), the touch screen/touch pad can be kept while one ormore other components are replaced, resoldered, reseated, orreconnected.

Example Internal Diagnostic Mechanism

FIG. 4 illustrates an internal diagnostic mechanism 345-1 coupled with atransmitter circuit 305-1, in accordance with an embodiment. In oneembodiment, internal diagnostic mechanism 345-1 is disposed on the samepiece of silicon as transmitter circuit 305-1, thus eliminating the needfor an external testing appliance. In various embodiments, as only a fewcomponents are needed to implement internal diagnostic mechanism 345-1,this is a very minimal addition to an overall ASIC or other integratedcircuit.

Transmitter circuit 305-1 is, in one embodiment, a tri-state digitaldriver that transmits an input (IN) signal and provides this signal atoutput (TX OUT) and onto transmitter path 190 (only a portion shown) inresponse to being enabled with an enable signal (EN). In one embodiment,transmitter circuit 305-1 is operable to drive the output (TX OUT) andthus transmitter path 190 at a selectable drive level or strength basedupon a strength input received at STR. In one embodiment, transmittercircuit 305-1 is operable to drive the output (TX OUT) and thustransmitter path 190 at a selectable speed or slew rate. Additionally,in the absence of an enable signal on EN, the output of TX OUT goes intoa tri-state mode that maintains transmitter path 190 at a highimpedance. It is appreciated that an input device may have one or moretransmitter circuits, such as transmitter circuit 305-1. For example, inone embodiment, there may be one or more transmitter circuits such as305-1 coupled to each transmitter electrode (e.g., transmitter electrode160-1) of an input device. Connector 410 is a conductive connector of anASIC, controller, or other integrated circuit in which transmittercircuit 305-1 is disposed.

Internal diagnostic mechanism 345-1 includes a buffered output OUT_1that is coupled to the output, TX OUT, of transmitter circuit 305-1. Asdepicted, buffering is provided by two series inverters INV1 and INV2.It is appreciated that other mechanisms may provide suitable buffering.In one embodiment, OUT_1 is provided to determination module 355. Asillustrated, in one embodiment, this may comprise a plurality of outputs(OUT_1, OUT_2, OUT_3, OUT_n) from each of a plurality of internaldiagnostic mechanisms 345 being multiplexed together by multiplexer 440into a single output line, OUT, that can be selected such bydetermination module 355 by providing a selection signal, SEL_B, tomultiplexer 440.

Internal diagnostic mechanism 345-1 also includes a selectable leakagepath 430 that can be selected with a diagnostic signal DIAG_1, whichcomprises an input select signal on selectable diagnostic node 431 ofselectable leakage path 430. Selectable leakage path 430 couplestransmitter path 190 to ground through transistor T1. As illustrated,the gate of transistor T1 is coupled through an inverter, INV1, to theenable input, EN, of transmitter circuit 305-1. In one embodiment,selectable leakage path 430 is only active when two selection mechanismsare both enabled. In various embodiments, the first selection mechanism,T1, is enabled when EN is low (not enabled). The second selectionmechanism, selectable diagnostic node 431, is enabled when DIAG_1 isenabled (high). Selectable leakage path 430 may be formed in a number ofways, such as with a selectable current source or with a selectable weakpull-down transistor disposed in series between transistor T1 andground.

Selectable leakage path 430 is a weak leakage path, where the term“weak” means that the path is weak enough that a fully charged nominal(not shorted or open) transmitter path 190 can be sampled a plurality oftimes before being discharged. In one embodiment, being discharged maybe represented by logic zero. The relative weakness is selected suchthat a desired granularity is provided by the number of nominalcondition (no shorts or opens) samples which should be able to beobtained. For example, in one embodiment, selectable leakage path 430may be designed to provide 10 nominal samplings (a very coarsegranularity) spaced at 10 nanosecond intervals prior to fullydischarging a fully charge transmitter path 190. Ten samplings mayprovide sufficient granularity in an embodiment where it is only desiredto determine if an open exists in transmitter path 190. In anotherembodiment, selectable leakage path 430 may be designed to provide 100nominal samplings (a finer granularity than ten samples) spaced at 10nanosecond intervals prior to fully discharging a fully chargedtransmitter path 190. One hundred samplings may provide sufficientgranularity in an embodiment where it is desired to determine if an openexists in transmitter path 190 and to further to estimate whichcomponent in transmitter path in which the open is located. By a sample,what is meant is that the output, OUT_1, is strobed and measured whilethe leakage path is enabled. The output is repeatedly strobed andmeasured at known, defined intervals (e.g., every 10 nanoseconds) untila strobed output of transmitter path 190 is measured as completelydischarged. In one embodiment, completely discharged is represented aslogic zero. Each strobing and measurement constitutes a sample. In thismanner, both the time (discharge rate) and number of samples that ittakes to reach full discharge can be measured by determination module355.

In one embodiment, the signal DIAG_1 is provided by determination module355 or some other portion of processing system 110A. In one embodiment,the signal DIAG_1 may be provided simultaneously to multiple internaldiagnostic mechanisms. In one other embodiment, a diagnostic input, isprovided to a demultiplexer and is routed as a particular diagnosticsignal to any of a plurality of internal diagnostic mechanisms. This isaccomplished by demultiplexing the DIAG signal to a selected internaldiagnostic mechanism in response to a selection signal. In variousembodiments, such demultiplexing allows for only a few signal lines tobe utilized in order for processing system 110A to direct input selectsignals to respective selectable leakage paths of a large number ofinternal diagnostic mechanisms.

Detecting Discontinuity

Determination module 355 can determine if a discontinuity exists along atransmitter path based upon a measurement of a discharge rate of thetransmitter path during a time period that occurs after it has beencharged by transmitter circuitry 305. This is because the discharge ratewill be longer for greater capacitance and shorter for lessercapacitance, and because the amount of capacitance loading is directlycorrelated to the length of a transmitter path. For example transmittercircuit 305-1 fully charges transmitter path 190 during a first timeperiod and is then disabled during a second time period. In oneembodiment, during the first time period, an enable signal sent tointernal diagnostic mechanism 345-1. During the second time period,internal diagnostic mechanism 345-1 and determination module 355 areutilized to measure the discharge rate of transmitter path 190. Bycomparing the discharge rate of transmitter path 190 with apredetermined discharge rate threshold value or range of values fortransmitter path 190, determination module 355 can determine iftransmitter path 190 has an open, as the discharge rate will be shorterthan a nominal discharge rate threshold value if there is an open in thetransmitter path, and will be progressively shorter than the nominaldischarge rate threshold value the closer that the open is located totransmitter circuit 305-1. This discharge rate will grow shorter as theopen is nearer transmitter circuit 305-1, because the open will causethe transmitter path to be shorter than normal and thus its capacitiveloading (in response to being driven) to be progressively less than thatof a nominal transmitter path 190.

In some embodiments a predetermined discharge rate threshold value (orrange of values) to which a measured discharge rate is compared can bedetermined from empirical data measured on a similar, nominal (no shortsor opens) transmitter path or can be modeled data for a similar, nominaltransmitter path. Likewise, additional predetermined thresholdvalues/ranges that are associated with location of an open in aparticular component or location on a transmitter path can be similarlydetermined from empirical or modeled data. In a manufacturing situation,such predetermined thresholds or ranges can be established once andutilized when testing numerous components (i.e., hundreds, thousands, ormillions) in a production run.

Detecting Ohmic Coupling

Determination module 355 can also use internal diagnostic mechanism345-1 and/or similar internal diagnostic mechanisms 345 that are coupledto other transmitter paths other than transmitter path 190 to determineif shorts exist between transmitter paths or between a transmitter pathand a reference voltage of an input device.

In one embodiment, similar to where discontinuity testing is beingaccomplished (as described above) and where the capacitive loading ishigher than expected (e.g., the discharge rate is longer than expectedbased on modeled or empirical data for a nominal transmitter path)rather than lower, determination module 355 can determine that the aportion of the tested transmitter path is ohmically coupled (e.g.,shorted to some extent) to a receiver path of the input device. In oneembodiment, an electrical path includes a receiver electrode such asreceiver electrode 170-1 and/or any elements coupled with receivercircuitry of processing system 110A, such as traces and correspondingconnections. This determination can be made because it would take suchshorting to create a longer path which can sustain the higher thannominal capacitive loading indicated by a longer than nominal dischargerate.

In one embodiment, while the first transmitter path 190 is being drivenby transmitter circuitry 305 and other transmitter paths are held at ahigh impedance by transmitter circuitry 305, determination module 355can measure the output from a second internal diagnostic mechanism thatis coupled with a second transmitter path to determine if any of thedriven signal bleeds over to the second transmitter path. If there isbleed over, then determination module 355 can determine that the firsttransmitter path is ohmically coupled (e.g., shorted) in some fashion tothe second transmitter path. Similar measurements can be taken from theoutputs of diagnostic mechanisms of a third or additional transmitterpaths to determine if any of these other transmitter paths is shorted tothe first transmitter path. In a further embodiment, an output of afirst internal diagnostic mechanism (e.g., 345-1 of FIG. 4) which iscoupled with a first transmitter path (e.g., transmitter path 190) canbe sampled to determine if a short exists in the first transmitter path.This procedure involves driving the first transmitter path to a highvalue with the path's transmitter circuit (e.g., transmitter circuit305-1) during a time period. If something less that the driven value ismeasured at the output of the first internal diagnostic mechanism whilethe driving is taking place, then determination module 355 determinesthat the transmitter path is shorted to ground or another transmitterpath.

In another embodiment, to determine if first transmitter path 190 isohmically coupled (e.g., shorted to some extent) to an adjacent (second)transmitter path, the second transmitter path can be driven bytransmitter circuitry 305 with an opposite signal to the signal that isbeing driven on the first transmitter path. Determination module 355determines that the first and second transmitter paths are ohmicallycoupled (shorted) if a value of zero is measured at the output, OUT_1,of the first internal diagnostic mechanism 345-1 or at the output (e.g.,OUT_2) of a second internal diagnostic mechanism that is coupled withthe second transmitter path. This technique can be similarly carried outbetween the first transmitter path 190 and a third transmitter pathwhere the third transmitter path is driven with a signal that isopposite of the signal driven on the first transmitter path, and anoutput value of zero is measured at the output, OUT_1, of the firstinternal diagnostic mechanism 345-1 or at the output (e.g., OUT_3) of athird internal diagnostic mechanism that is coupled with the thirdtransmitter path. For example, transmitter path 190 may be a middletransmitter path with the second transmitter path adjacent on one sideand the third transmitter path adjacent on another side. In otherembodiments, the technique utilized to detect a short between firsttransmitter path 190 and a second transmitter path can be rolled throughbetween first transmitter path 190 and each additional transmitter pathof an input device. Similar tests can then be conducted between eachpossible paring of two transmitter paths in an input device.

In yet another embodiment, to determine if first transmitter path 190 isohmically coupled (e.g., shorted to some extent) to a referencepotential, a transmitter signal is transmitted on transmitter path 190by transmitter circuit 305-1. While the transmitter signal is beingtransmitted, other transmitter paths are maintained at a high impedanceand determination module 355 selects or enables the output of firstinternal diagnostic mechanism 345-1 so that it may measure the resultingsignal at the output, OUT_1. From this sampled resulting signal at theoutput of internal diagnostic mechanism 345-1, determination module 355determines if the first transmitter path is ohmically coupled to areference potential (e.g., ground or some internal voltage of the) ofthe input device. For example, in one embodiment if the measuredresulting signal is low (e.g., logic zero) it can be determined that thetransmitter path has an ohmic coupling to a ground, and if the measuredresulting signal is high (e.g., logic one) than expected it can bedetermined that the transmitter path is ohmically coupled to a referencevoltage that is higher than ground potential. In another embodiment, ifthe measured resulting signal is lower than expected it can bedetermined that the transmitter path has an ohmic coupling to a ground,and if the measured resulting signal is higher than expected it can bedetermined that the transmitter path is ohmically coupled to a referencevoltage that is higher than ground potential

Example Method of Input Device Transmitter Path Error Diagnosis

FIGS. 5A, 5B, and 5C illustrate a flow diagram of an example method ofinput device transmitter path error diagnosis, in accordance withembodiments. For purposes of illustration, during the description offlow diagram 500, reference will be made to components of processingsystem 110A of FIG. 3 and to transmitter circuit 305-1 and components ofinternal diagnostic circuit 345-1 of FIG. 4. In some embodiments, notall of the procedures described in flow diagram 500 are implemented. Insome embodiments, other procedures in addition to those described may beimplemented. In some embodiments, procedures described in flow diagram500 may be implemented in a different order than illustrated and/ordescribed.

At 510 of flow diagram 500, in one embodiment, the method transmitsduring a first time period with a first transmitter path of a pluralityof transmitter paths in an input device. It is appreciated that thetransmitter paths are each configured for capacitive sensing and thuseach transmitter path includes a transmitter electrode such astransmitter electrode 160-1 of FIG. 1B. With reference to FIG. 4, in oneembodiment, if transmitter path 190 is considered to be the firsttransmitter path, this comprises transmitter circuit 305-1 transmittingvia TX OUT onto transmitter path 190.

At 520 of flow diagram 500, in one embodiment, a selectable leakage pathof an internal diagnostic mechanism of the processing system is enabledduring a second time period. The second time period is separate from andfollowing the first time period. With further reference FIG. 4, in oneembodiment, during the second time period EN becomes disabled, thusturning on transmitter T1 during the second time period. During thissecond time period processing system 110A then provides an enabling inthe form of DIAG_1 on node 431 in order to enable selectable leakagepath 430.

At 530 of flow diagram 500, in one embodiment, it is determined if adiscontinuity (i.e., an open) exists within the first transmitter path.For example, determination module 355 makes this determination based ona measured discharge rate for the first transmitter path. The dischargerate is acquired during a second time period via the selectable leakagepath of the internal diagnostic mechanism (e.g., 345-1) of a processingsystem of the input device.

At 540 of flow diagram 500, in one embodiment, the method furtherincludes transmitting a first transmitter signal with the firsttransmitter path during a third time period. The third time period maybe the same as the first time period or may be later than the secondtime period. The transmitter signal may be a signal such as a squarewave, trapezoidal wave, or some other waveform that is transmitted withthe first transmitter path (e.g., transmitter path 190) by a transmittercircuit (e.g., transmitter circuit 305-1) of transmitter circuitry 305.

At 550 of flow diagram 500 while transmitting the first transmittersignal at procedure 540, in one embodiment, the method also determinesif the first transmitter path is ohmically coupled to a secondtransmitter path of the plurality of transmitter paths. For example,determination module 355 makes this determination, in one embodiment,based upon a first resulting signal that is measured at an output of asecond internal diagnostic mechanism coupled to the second transmitterpath. The second resulting signal is acquired via the output of thesecond internal diagnostic mechanism while transmitting the firsttransmitter signal with the first transmitter path. It is appreciatedthat the second internal diagnostic mechanism is, in one embodiment, anidentical circuit to that of first internal diagnostic mechanism 345-1except that it is coupled with the second transmitter path. OUT_2,illustrated in FIG. 4, is an example of the output from such a secondinternal diagnostic mechanism.

At 560 of flow diagram 500, in one embodiment, the method furtherincludes determining if the first transmitter path is ohmically coupledto a third transmitter path of the plurality of transmitter paths.Similarly to procedure 550, determination module 355 makes thisdetermination, in one embodiment, based on a second resulting signalreceived at an output of a third internal diagnostic mechanism coupledwith the third transmitter path. The second resulting signal is acquiredvia the output of the third internal diagnostic mechanism whiletransmitting the first transmitter signal with first transmitter path.It is appreciated that the third internal diagnostic mechanism is, inone embodiment, an identical circuit to that of first internaldiagnostic mechanism 345-1 except that it is coupled with the thirdtransmitter path. OUT_3, illustrated in FIG. 4, is an example of theoutput from such a third internal diagnostic mechanism. The secondtransmitter signal may be the same or different from the firsttransmitter signal, and may be a square wave, trapezoidal wave, or someother waveform.

At 570 of flow diagram 500, in one embodiment, the method as describedin 510 through 530 further includes determining if the first transmitterpath is ohmically coupled to a receiver path of the capacitive sensingdevice. Determination module 355 makes this determination, in oneembodiment, based on a comparison of a measurement of capacitive loadingof the first transmitter path to a predetermined capacitive loadingthreshold value. The predetermined capacitive loading threshold valuemay be acquired from empirical or modeled data, but is for a nominal(neither shorted nor open) version of the first transmitter path. Thecapacitive loading threshold may be expressed as a discharge rate ortime that it should take to discharge the first transmitter path via aselectable leakage path of an internal diagnostic mechanism. If theactually measured capacitive loading is greater than the predeterminedthreshold by a predetermined margin (e.g., 10% or greater, as but onenon-limiting example), then determination module 355 determines that thefirst transmitter path is shorted to a receiver path.

At 580 of flow diagram 500, in one embodiment, the method as describedin 510 through 530 further includes determining if the discontinuityexists based on a comparison of a measurement of capacitance of thefirst transmitter path to a predetermined transmitter path capacitancethreshold value. The measurement of capacitance is acquired via theselectable leakage path. For example, it is enabled and the output isstrobed (sampled) repeatedly at regular intervals to determine a measureof capacitance indirectly by measuring the discharge rate (the time thatit takes until the transmitter path is measured to be fully dischargedor reach logic zero).

Thus, the embodiments and examples set forth herein were presented inorder to best explain various selected embodiments of the presentinvention and its particular application and to thereby enable thoseskilled in the art to make and use embodiments of the invention.However, those skilled in the art will recognize that the foregoingdescription and examples have been presented for the purposes ofillustration and example only. The description as set forth is notintended to be exhaustive or to limit the embodiments of the inventionto the precise form disclosed.

What is claimed is:
 1. A processing system configured for capacitivesensing, said processing system comprising: transmitter circuitrycoupled with a first transmitter path of a plurality of transmitterpaths and configured to transmit a first transmitter signal with saidfirst transmitter path, wherein each transmitter path of said pluralityof transmitter paths is configured for capacitive sensing; a firstinternal diagnostic mechanism coupled to a second transmitter path ofsaid plurality of transmitter paths, said first internal diagnosticmechanism configured to acquire a first resulting signal while saidtransmitter circuitry transmits said first transmitter signal with saidfirst transmitter path, wherein said first internal diagnostic mechanismcomprises a selectable leakage path coupled to said transmittercircuitry; and a determination module is further configured to determinethat said first transmitter path is ohmically coupled to said secondtransmitter path of said plurality of transmitter paths based upon saidfirst resulting signal.
 2. The processing system of claim 1, whereinsaid determination module is further configured to determine when saidfirst transmitter path is ohmically coupled to a third transmitter pathof said plurality of transmitter paths based on a second resultingsignal at an output of a second internal diagnostic mechanism coupledwith said third transmitter path, wherein said second resulting signalis acquired via said output of said second internal diagnostic mechanismwhile said transmitter circuitry transmits said first transmitter signalwith said first transmitter path.
 3. The processing system of claim 1,wherein said transmitter circuitry is further configured to transmit asecond transmitter signal on said second transmitter path while saidfirst transmitter signal is transmitted on said first transmitter path,wherein said second transmitter signal is of opposite polarity to saidfirst transmitter signal.
 4. The processing system of claim 1 furthercomprising a second internal diagnostic mechanism coupled said firsttransmitter path, wherein: said transmitter circuitry is furtherconfigured to transmit a second transmitter signal with said secondtransmitter path; said second internal diagnostic mechanism is furtherconfigured to enable an output of said second internal diagnosticmechanism; and said determination module is further configured todetermine when said first transmitter path is ohmically coupled to areference potential based on a measurement of a second resulting signal,wherein said second resulting signal is acquired via said output of saidsecond internal diagnostic mechanism while said transmitter circuitrytransmits said second transmitter signal with said second transmitterpath.
 5. The processing system of claim 1, wherein said transmittercircuitry is further configured to transmit said first transmittersignal with said second transmitter path; and said determination moduleis configured to determine when said second transmitter path isohmically coupled to a third transmitter path of said plurality oftransmitter paths based on a second resulting signal at an output of asecond internal diagnostic mechanism coupled with said third transmitterpath, wherein said second resulting signal is acquired via said outputof said second internal diagnostic mechanism while said transmittercircuitry transmits said first transmitter signal with said secondtransmitter path.
 6. The processing system of claim 1, wherein saidfirst internal diagnostic mechanism is configured to couple said secondtransmitter path with a constant voltage during a first time period andwherein said determination module is configured to determine when adiscontinuity exists within said second transmitter path based on anoutput of said first internal diagnostic mechanism during a second timeperiod, wherein said second time period occurs after said first timeperiod.
 7. The processing system of claim 1, wherein said determinationmodule is further configured to determine when said first transmitterpath is ohmically coupled to at least one receiver path of a capacitivesensing device based on a comparison of a measurement of capacitiveloading of said first transmitter path to a predetermined capacitiveloading threshold value.
 8. The processing system of claim 1, whereinsaid first internal diagnostic mechanism further comprises a bufferedoutput coupled with said selectable leakage path and said secondtransmitter path, and a selectable diagnostic node coupled as an inputselect of said selectable leakage path.
 9. The processing system ofclaim 1, wherein said selectable leakage path comprises a weak pull-downtransistor.
 10. The processing system of claim 1, wherein saidselectable leakage path comprises a current source.
 11. The processingsystem of claim 1, wherein said first internal diagnostic mechanism isfurther coupled to a third transmitter path of said plurality oftransmitter paths, said first internal diagnostic mechanism configuredto acquire a second resulting signal with said third transmitter pathwhile said transmitter circuitry transmits said first transmitter signalwith said first transmitter path.
 12. A capacitive sensing devicecomprising: a plurality of transmitter paths, wherein each transmitterpath of said plurality of transmitter paths is configured for capacitivesensing; and a processing system coupled with said plurality oftransmitter paths, said processing system configured to: transmit afirst transmitter signal with a first transmitter path of said pluralityof transmitter paths in an input device; acquire a first resultingsignal from an output of a first internal diagnostic mechanism coupledto a second transmitter path of said plurality of transmitter pathswhile said processing system transmits said first transmitter signalwith said first transmitter path; and determine when said firsttransmitter path is ohmically coupled to said second transmitter path ofsaid plurality of transmitter paths based upon said first resultingsignal.
 13. The capacitive sensing device of claim 12, wherein saidprocessing system is further configured to determine when said firsttransmitter path is ohmically coupled to a third transmitter path ofsaid plurality of transmitter paths based on a second resulting signalat an output of a second internal diagnostic mechanism coupled with saidthird transmitter path, wherein said second resulting signal is acquiredvia said output of said second internal diagnostic mechanism while saidprocessing system transmits said first transmitter signal with saidfirst transmitter path.
 14. The capacitive sensing device of claim 12,wherein said processing system is further configured to: transmit asecond transmitter signal with said second transmitter path; enable anoutput of a second internal diagnostic mechanism coupled to said firsttransmitter path; and determine when said first transmitter path isohmically coupled to a reference potential based on a measurement of asecond resulting signal, wherein said second resulting signal isacquired via said output of said second internal diagnostic mechanismwhile transmitting said second transmitter signal with said secondtransmitter path.
 15. The capacitive sensing device of claim 12, whereinsaid processing system is further configured to transmit said firsttransmitter signal with said second transmitter path and to determinewhen said second transmitter path is ohmically coupled to a thirdtransmitter path of said plurality of transmitter paths based on asecond resulting signal at an output of a second internal diagnosticmechanism coupled with said third transmitter path, wherein said secondresulting signal is acquired via said output of said second internaldiagnostic mechanism while transmitting said first transmitter signalwith said second transmitter path.
 16. The capacitive sensing device ofclaim 12, wherein said processing system is configured to couple saidsecond transmitter path with a constant voltage during a first timeperiod via said first internal diagnostic mechanism and wherein saidprocessing system is further configured to determine when adiscontinuity exists within said second transmitter path based on anoutput of said first internal diagnostic mechanism during a second timeperiod, wherein said second time period occurs after said first timeperiod.
 17. The capacitive sensing device of claim 12, wherein an outputof said first internal diagnostic mechanism is coupled with amultiplexer.
 18. A method of input device transmitter path errordiagnosis, said method comprising: transmitting a first transmittersignal with a first transmitter path of a plurality of transmitter pathsin an input device, wherein each transmitter path of said plurality oftransmitter paths is configured for capacitive sensing; acquiring afirst resulting signal from an output of a first internal diagnosticmechanism coupled to a second transmitter path of said plurality oftransmitter paths while transmitting said first transmitter signal withsaid first transmitter path; and determining when said first transmitterpath is ohmically coupled to said second transmitter path of saidplurality of transmitter paths based upon said first resulting signal.19. The method as recited in claim 18 further comprising: determiningwhen said first transmitter path is ohmically coupled to a thirdtransmitter path of said plurality of transmitter paths based on asecond resulting signal at an output of a second internal diagnosticmechanism coupled with said third transmitter path, wherein said secondresulting signal is acquired via said output of said second internaldiagnostic mechanism while transmitting said first transmitter signalwith said first transmitter path.
 20. The method as recited in claim 18further comprising: coupling said second transmitter path with aconstant voltage during a first time period via said first internaldiagnostic mechanism and determining when a discontinuity exists withinsaid second transmitter path based on an output of said first internaldiagnostic mechanism during a second time period, wherein said secondtime period occurs after said first time period.